1. Field of Disclosure
The disclosure relates to the field of voice over internet protocol (VoIP) emergency call services.
2. Description of the Related Art
All telecommunication providers in the United States are now required by FCC rules to support 911 emergency call services. Based on these rules, when a telephony user dials 9-1-1, the telecommunication carrier must be able to process the call with the originating location information and route the 911 call to an appropriate PSAP (Public Safety Answering Point) Center that serves the caller's current location. For traditional PSTN (Public Switched Telephony Network) providers, the 911 support is based on the fact that telephone numbers are tied to fixed locations. Telecommunication providers usually store a subscriber's location (street address, etc.) in a database associated with an assigned telephone number (call back number (CBN)) during the subscriber service activation. When a user makes a 911 call, his calling telephone number (CBN) from the incoming call signal can be used to look up a caller's location information, and use the retrieved information to route the 911 call to a serving PSAP proximate to the caller's location.
The introduction of Voice over IP (VoIP) technology raises a different challenge to service providers to support 911 services. This is because a VoIP user can easily move his/her VoIP phone from one location to another, plug in to a visited local area network (LAN), register to the VoIP service provider, and start to make and receive phone calls at the new location. This mobile capability of VoIP phones eliminates the dedicated correlation between telephone number and a user physical location.